Intra and Interspecific Variations of Yield and Chemical Composition of Essential Oils From Five Eucalyptus Species Growing in the Congo-Brazzaville. Corymbia Subgenus

Abstract

Leaf essential oils obtained by hydrodistillation from Eucalyptus citriodora Hook., E. torelliana Hook., E. maculata Hook., E. nesophila Blakely and E. polycarpa F. Muell. (genus Eucalyptus, subgenus Corymbia) were analyzed by GC and GC/MS. The oil contents from the leaves of E. citriodora and E. maculata were greater than 2%; while the oils from the leaves of E. torelliana, E. nesophila and E. polycarpa were less than 1%. With the exception of E. citriodora oil, the composition of the other oils were found to vary significantly according species and the individual trees. Eucalyptus citriodora oil was a citronellal type (citronellal: 64.5–75.4%; citronellol: 8–11%). The main chemical types of E. torelliana in the Congo-Brazzaville were the pinene-type (17–78%), the citronellyl acetate-type (55.5%), and the globulol-type (20–26%). The major components of the E. nesophila oils were either α-pinene, or viridiflorol, which suggests the existence of an α-pinene-type and a viridiflorol-type. Eucalyptus polycarpa oils were found to be mainly rich in β-pinene (14–41%), globulol (20%), viridiflorol (23.4%), aromadendrene (8.3%) and γ-terpinene (5%).